Screening of Locally Available Lemon Grass (Cymbopogon citratus) for Repellency Action against Aedes aegypti

In Nigeria, re-emergence of diseases caused by Aedes mosquito borne pathogens, and challenges associated with existing control tools occur. This necessitates an improved insecticide-based tool for use in Integrated Vector Management. So, repellent action of Cymbopogon citratus essential oil (EO) on Aedes aegypti (Linn.) was tested. The EO from C. citratus plant sourced from Awka, was extracted by hydro distillation, and the phytochemicals analyzed by Gas Chromatography-Mass Spectrometry. Repellent action of the EO on unfed Ae. aegypti was assessed using "WHO arm-in-cage" method. In triplicate, arms of human volunteers were treated with different concentrations (50.0, 25.0, 12.5, 6.25 and 3.125 % v/v) of the EO and submitted to 25-caged, unfed Ae. aegypti for 1 minute in every 30 minutes. β-cedrenes, kaempferol, and thujopsene dominated the 13 phytochemicals identified. The standard (Odomos®) and all EO concentrations recorded 100 % repellency on application. At 30 minutes, EC99.9 value was25.0 %, concentrations ≥ 62.5 % v/v gave 100 % repellency (p > 0.05). At 60 minutes, EC99.9 value was 30.68 %, concentrations ≥ 12.5 % v/v gave 100 % repellency (p > 0.05). At 90 to 120 minutes, 50 % concentration maintained 100 % repellency (p < 0.05), EC99.9 value was 48.79 % at 120 minutes. Recording 120 minutes protection time with no adverse effect, 50 % concentration showed equal potency as Odomos®. Research to isolate the active ingredients in the EO for incorporation into beneficial health and economic products is desirable.

The Impact of Space Radiation Environment on Satellites Operation in Near-Earth Space

Energetic particles and electromagnetic radiation (EM) from solar events and galactic cosmic rays can bombard and interact with satellites’ exposed surfaces, and sometimes possess enough energy to penetrate their surface. Among other known effects, the scenario can cause accelerated orbit decay due to atmospheric drag, sporadic and unexplainable errors in functions of sensitive parts, degradation of critical properties of structural materials, jeopardy of flight worthiness, transient and terminal health hazard to both onboard passengers and astronauts, and sometimes a catastrophic failure that can abruptly end satellite mission. The understanding of the dynamics of the space radiation environment and associated effects is critically important for satellites design and operation in ionospheric plasma environment, in which satellites are designed to function. In this chapter we review some satellite anomalies associated with the space radiation environment and conclude with mitigation effort that can reduce such impact

Mobile health use predicts self-efficacy and self-management in adolescents with sickle cell disease

Sickle cell disease (SCD) is associated with significant health challenges that often worsen during adolescence. Living with SCD requires a substantial amount of self-management and mobile health (mHealth) holds considerable promise for assessing and changing behaviors to improve health outcomes. We integrated a mobile app as an adjunct to a group intervention (SCThrive) and hypothesized that more engagement with the mHealth app would increase self-management and self-efficacy for adolescents and young adults (AYA) with SCD. Twenty-six AYA ages 13–21 years (54% female; 46% HbSS genotype; all African-American/Black) received six weekly group sessions (three in-person, three online). Participants were provided with the mobile app (iManage for SCD) to record progress on their self-management goals and log pain and mood symptoms. The Transition Readiness Assessment Questionnaire (TRAQ-5) assessed self-management skills and the Patient Activation Measure (PAM-13) assessed self-efficacy at baseline and post-treatment. Logging on to the app more frequently was associated higher mood ratings (r = .54, CI[.18, .77], p = .006) and lower pain ratings (r = −.48, CI[−.77, −.02], p = .04). Regression analyses demonstrated that after controlling for scores at baseline, the number of logins to the app predicted self-management skills (p = .05, η2 = .17) and possibly self-efficacy (p = .08, η2 = .13). Our study findings indicate that it can be challenging to maintain engagement in mHealth for AYA with SCD, but for those who do engage, there are significant benefits related to self-management, self-efficacy, and managing pain and mood

Luminosity distance and redshift in the Szekeres inhomogeneous cosmological models

The Szekeres inhomogeneous models can be used to model the true lumpy universe that we observe. This family of exact solutions to Einstein's equations was originally derived with a general metric that has no symmetries. In this work, we develop and use a framework to integrate the angular diameter and luminosity distances in the general Szekeres models. We use the affine null geodesic equations in order to derive a set of first-order ordinary differential equations that can be integrated numerically to calculate the partial derivatives of the null vector components. These equations allow the integration in all generality of the distances in the Szekeres models and some examples are given. The redshift is determined from simultaneous integration of the null geodesic equations. This work does not assume spherical or axial symmetry, and the results will be useful for comparisons of the general Szekeres inhomogeneous models to current and future cosmological data.Comment: 14 pages, 1 figure, matches JCAP accepted versio